NASA Scientists Get First Images of Earth Flyby Asteroid
January 25, 2008
Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif.,
have obtained the first images of asteroid 2007 TU24 using high-resolution
radar data. The data indicate the asteroid is somewhat asymmetrical in
shape, with a diameter roughly 250 meters (800 feet) in size. Asteroid
2007 TU24 will pass within 1.4 lunar distances, or 538,000 kilometers
(334,000 miles), of Earth on Jan. 29 at 12:33 a.m. Pacific time
(3:33 a.m. Eastern time).
"With these first radar observations finished, we can guarantee that
next week's 1.4-lunar-distance approach is the closest until at least
the end of the next century," said Steve Ostro, JPL astronomer and principal
investigator for the project. "It is also the asteroid's closest Earth
approach for more than 2,000 years."
Scientists at NASA's Near-Earth Object Program Office at JPL have
determined that there is no possibility of an impact with Earth in
the foreseeable future.
Asteroid 2007 TU24 was discovered by the NASA-sponsored Catalina Sky Survey
on Oct. 11, 2007. The first radar detection of the asteroid was acquired
on Jan. 23 using the Goldstone 70-meter (230-foot) antenna. The Goldstone
antenna is part of NASA's Deep Space Network Goldstone station in Southern
California's Mojave Desert. Goldstone's 70-meter diameter (230-foot) antenna
is capable of tracking a spacecraft traveling more than 16 billion kilometers
(10 billion miles) from Earth. The surface of the 70-meter reflector must
remain accurate within a fraction of the signal wavelength, meaning that
the precision across the 3,850-square-meter (41,400-square-foot) surface
is maintained within one centimeter (0.4 inch).
Ostro and his team plan further radar observations of asteroid 2007 TU24
using the National Science Foundation's Arecibo Observatory in Puerto Rico
on Jan. 27-28 and Feb. 1-4.
The asteroid will reach an approximate apparent magnitude 10.3 on Jan. 29-30
before quickly becoming fainter as it moves farther from Earth. On that night,
the asteroid will be observable in dark and clear skies through amateur telescopes
with apertures of at least 7.6 centimeters (three inches). An object with a
magnitude of 10.3 is about 50 times fainter than an object just visible to the
naked eye in a clear, dark sky.
Scientists working with Ostro on the project include Lance Benner and Jon
Giorgini of JPL, Mike Nolan of the Arecibo Observatory, and Greg Black of the
University of Virginia.
NASA detects and tracks asteroids and comets passing close to Earth. The Near
Earth Object Observation Program, commonly called "Spaceguard," discovers,
characterizes and computes trajectories for these objects to determine if any
could be potentially hazardous to our planet. The Arecibo Observatory is part
of the National Astronomy and Ionosphere Center, a national research center
operated by Cornell University, Ithaca, N.Y., for the National Science
Foundation. JPL is a division of the California Institute of Technology in Pasadena.
For more information, visit http://neo.jpl.nasa.gov .
Media contact: Contact: DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
Grey Hautaluoma 202-358-0668